Topology Optimization

This paper presents a density-based topology optimization method for designing 3D thin-walled structures with adaptive meshing. Uniform wall thickness is achieved by simultaneously constraining the minimum and maximum feature sizes using Helmholtz partial differential equations (PDE). The PDE-based constraints do not require information about neighbor cells and therefore can readily be integrated with an adaptive meshing scheme. This effectively enables the 3D topology optimization of thin-walled structures with a desktop PC, by significantly reducing computation in large void regions that appear during optimization. The uniform feature size constraint, when applied to 3D structures, can produce thin-walled geometries with branches and holes, which have previously been difficult to obtain via topology optimization. The resulting thin-walled structures can provide valuable insights for designing thin-walled lightweight structures made of stamping, investment casting and composite manufacturing.

A new force visualization and design tool employing hybrid topology optimization is introduced for RC and prestressed concrete structural members. The optimization scheme couples a minimum compliance (maximum stiffness) objective function with a hybrid trusscontinuum ground structure that can generate a strut-and-tie model for any general concrete member, loading, and set of boundary conditions. The truss ground structure represents discrete steel reinforcing bars (tensile load paths) that can be sized based on axial forces output directly by the optimization routine, whereas the continuum elements simulate concrete compression struts. This separation of compressive and tensile load-carrying elements is achieved through bilinear elastic models with an orthotropic constitutive relationship for the continuum. Examples are provided demonstrating the potential value of the optimization tool to RC design. Reinforcing layouts that can minimize cracking and reduce steel quantities when compared with traditional designs are provided for a prismatic beam, a hammerhead pier, a stepped beam with a cutout, and the local anchorage zone of a prestressed concrete block. A minimum length scale constraint is employed to control complexity of the strutand-tie topology, accommodating design solutions that balance material savings, structural performance, and constructability.

Topology optimization is the most important part of structural optimization which is employed when the design is at the conceptual stage. Generally topology optimization gives an optimal material distribution of a design domain while minimizing the compliance of the structure. In this work focus has been kept on some practical design domains to get the actual structures after topology optimization using finite element solver ANSYS. ANSYS employs topology optimization using the Solid Isotropic Material with Penalization (SIMP) scheme for the penalization of the intermediate design variables and the Optimality Criterion for updating the design variables. 8 node 82 and solid 95 elements are used to model and mesh the isotropic structures in ANSYS.

Structural vibration is the most significant source of structure-borne noise. Avoiding severe resonances of the structures in order to reduce noise generation is the main interest of engineering fields. This paper studied a typical example of the structure-borne noise reduction utilized in general engineering practices. Noise measurement and experimental modal analysis demonstrated that some resonance modes of the structure contribute highly to noise generation.

Wireless Community Networks (WCNs) are bottom-up broadband networks empowering people with their on-line communication means. Too often, however, services tailored for their characteristics are missing, with the consequence that they have worse performance than what they could. We present here an adaptation of an Open Source P2P live streaming platform that works efficiently, and with good application-level quality, over WCNs. WCNs links are usually symmetric, or at least asymmetry is not by design as it is in ADSL, and a WCN topology is local and normally flat (contrary to the the global Internet), so that the P2P overlay used for video distribution can be adapted to the underlaying network characteristics. We exploit this observation to derive over- lay building strategies that make use of cross-layer information to reduce the impact of the P2P streaming on the WCN while maintaining good application performance. We experiment with a real application in real WCN nodes, both in the Community-Lab provided by the CONFINE EU Project and within an emulation framework based on Mininet, where we can build larger topologies and interact more efficiently with the mesh underlay, which is unfortunately not accessible in Community-Lab. The results show that, with the overlay building strategies proposed, the P2P streaming applications can reduce the load on the WCN to about one half, also equalizing the load on links. At the same time the delivery rate and delay of video chunks are practically unaffected.

The feasibility of using the topology design method for structural damage identification is investigated for the first time. The finite element model of an undamaged structure and some point-frequency response functions of a damaged structure are assumed to be available. To carry out the feasibility study, the topology optimization formulation suitable for structural damage detection is newly set up, where both resonances and anti-resonances are used as the damage indication modal parameters. An idea to progressively reduce the candidate damaged elements is also developed to improve the accuracy and efficiency of the proposed method. Figure 3. The overview of the progressive design variable reduction (PR) strategy, especially for the small-sized damage identification. DAMAGE DETECTION BY THE TOPOLOGY DESIGN FORMULATION 1489 3. NUMERICAL CASE STUDIES

The paper is concentrated on two essential problems: neural networks topology optimization and weights parameters computation that are often solved separately. This paper describes new solution of solving both selected problems together. According to proposed methodology a special kind of multilayer ontogenic neural networks called Self-Optimizing Neural Networks (SONNs) can simultaneously develop its structure for given training data and compute

Recently, smoothly-deforming aircraft structures have been investigated for their ability to adapt to varying flight conditions. Researchers aim to achieve large changes in the shape of the wings: area changes of up to 50% and aspect-ratio changes of up to 200% are being pursued. The research described in this paper aims to develop a structural concept capable of achieving continuous stable deformations over a large range of aircraft shapes. The basic concept underlying the approach is a compliant cellular truss, with tendons used as active elements. The truss members of the unit cell are connected through compliant joints such that only modest bending moments may be transmitted from one member to another. Actuation is achieved by pulling on one set of cables while releasing another set. The tendonactuated compliant truss can be made to behave locally, and temporarily, as a nearmechanism, by releasing appropriate cables. As a result, in the absence of aerodynamic forces, the structure can be morphed using relatively low forces. The cables are reeled in or released in a controlled manner while the structure is loaded, hence, the stability of the structure can be maintained in any intermediate position. Highly-distributed actuation also enables the simultaneous achievement of global shape changes as the accumulation of local ones, while the use of compliant joints rather than true rotating joints eliminates binding as a significant concern. A six-noded octahedral cell with diagonal tendon actuation is developed for a bending type deformation in the wing. Initial cell geometry is determined by "strain matching" to the local morphing deformation required by the application. A finite element analysis is performed on a wing made of these unit cells and sized for a representative UAV weighing 3000 lbs. The areas of the individual truss members are sized so that they don't fail or buckle under the air loads, while deflection at the wing tip is reduced. The octahedral unit cell is capable of achieving smooth deformations of the truss structure. The cell size is dictated by the available space and the morphing strain. The cell sizes are reasonable for strains on the order of 10% to 15% and get smaller for larger strains. Additional cell shapes are being investigated for larger area changes through a process of topology optimization using genetic algorithms. Numerous other technical challenges remain, including the details of actuation and a robust skin.

The paper begins with a brief historical overview of pressure adaptive materials and structures. By examining avian anatomy, it is seen that pressure-adaptive structures have been used successfully in the Natural world to hold structural positions for extended periods of time and yet allow for dynamic shape changes from one flight state to the next. More modern pneumatic actuators, including FAA certified autopilot servoactuators are frequently used by aircraft around the world. Pneumatic artificial muscles (PAM) show good promise as aircraft actuators, but follow the traditional model of load concentration and distribution commonly found in aircraft. A new system is proposed which leaves distributed loads distributed and manipulates structures through a distributed actuator. By using Pressure Adaptive Honeycomb (PAH), it is shown that large structural deformations in excess of 50% strains can be achieved while maintaining full structural integrity and enabling secondary flight control mechanisms like flaps. The successful implementation of pressure-adaptive honeycomb in the trailing edge of a wing section sparked the motivation for subsequent research into the optimal topology of the pressure adaptive honeycomb within the trailing edge of a morphing flap. As an input for the optimization two known shapes are required: a desired shape in cruise configuration and a desired shape in landing configuration. In addition, the boundary conditions and load cases (including aerodynamic loads and internal pressure loads) should be specified for each condition. Finally, a set of six design variables is specified relating to the honeycomb and upper skin topology of the morphing flap. A finite-element model of the pressure-adaptive honeycomb structure is developed specifically tailored to generate fast but reliable results for a given combination of external loading, input variables, and boundary conditions. Based on two bench tests it is shown that this model correlates well to experimental results. The optimization process finds the skin and honeycomb topology that minimizes the error between the acquired shape and the desired shape in each configuration.

In multi-objective optimization, a design is defined to be pareto-optimal if no other design exists that is better with respect to one objective, and as good with respect to other objectives. In this paper, we first show that if a topology is pareto-optimal, then it must satisfy certain properties associated with the topological sensitivity field, i.e. no further comparison is necessary. This, in turn, leads to a deterministic, i.e. non-stochastic, method for efficiently generating pareto-optimal topologies using the classic fixedpoint iteration scheme. The proposed method is illustrated, and compared against SIMP-based methods, through numerical examples. In this paper, the proposed method of generating pareto-optimal topologies is limited to bi-objective optimization, namely compliance-volume and compliance-compliance. The future work will focus on extending the method to non-compliance and higher dimensional pareto optimization.

This research offers a fundamental new approach to topology optimization. To date, topological synthesis approaches are simply augmentations of existing stochastic optimization techniques. While these algorithms are useful in complex parametric design spaces, they are not designed for all topology problems. This paper describes a generalized scheme for solving topological design problems. The approach combines aspects of existing optimization techniques, graph theory, mathematical programming, artificial intelligence, and shape and graph grammars. Specifically, the approach has advantages over modified parametric optimization algorithms in that 1) a two stage technique to developing solutions and searching the parametric design space more closely models the design process performed by humans and more thoroughly maps how various topologies are represented, 2) a graph grammar for generating candidate solutions minimizes the wasted search of infeasible topologies, and 3) a new stochastic guidance strategy intelligently distinguishes and independently controls the variables that alter topologies and the variables that represent dimensions and parameters. This automated design synthesis method is currently being developed to synthesize the best graph for a various applications, where the choice of nodes in the graph and how they are to be connected is determined through computational search. Such topological problems are prevalent in engineering design. Examples include truss structures, designing sheet metal components, designing the location and connection of roadways, and designing the choice and connection of processors in a chemical plant.

We demonstrate and optically characterize silicon-on-insulator based nanophotonic devices fabricated by nanoimprint lithography. In our demonstration, we have realized ordinary and topology-optimized photonic crystal waveguide structures. The topology-optimized structures require lateral pattern definition on a sub 30-nm scale in combination with a deep vertical silicon etch of the order of ~300 nm. The nanoimprint method offers a cost-efficient parallel fabrication process with state-of-the-art replication fidelity, comparable to direct electron beam writing.

The use of Fused Deposition Modelling (FDM) is increasing rapidly in both the commercial and industrial sectors as a means of rapidly prototyping geometrically complex parts. Particular affordances of FDM include the reduction of waste material during manufacture, the use of multiple materials within a single manufacturing process and the ability to manipulate the internal geometry of a part. The latter of which has seen the generation of many 2-dimensional repeating pattern structures such as square, rectilinear and hexagonal, as well as an emerging field of 3-dimensional structures. Although these patterns have provided stiffness and rigidity whilst reducing the production time of FDM prototypes, many do not consider the actual loading conditions of the part in-situ, where it is argued that further significant gains in the performance could be achieved. This includes further reduction in process time and increased part functionality.

Thus, this paper presents initial work into the generation of an infill that is derived from the predicted stress profile for the part. This has been achieved through the post-processing of Finite Element (FE) models to identify the stress profile. Interpolation across these profiles leads to a set of aligned Bezier splines that enable the transmission of force and are also able to be manufactured using FDM. These splines are embedded within the typical slicing procedure of a part ahead of being manufactured on a FDM machine. Initial results from parts designed to support three-point bending loads show a 79% increase in the stiffness of the part alongside a consistent and repeatable mode of failure when compared to the commonly used honeycomb infill design.

This paper deals with the applications of stochastic spectral methods for structural topology optimization in the presence of uncertainties. A non-intrusive polynomial chaos expansion is integrated into a topology optimization algorithm to calculate low-order statistical moments of the mechanical–mathematical model response. This procedure, known as robust topology optimization, can optimize the mean of the compliance while simultaneously minimizing its standard deviation. In order to address possible variabilities in the loads applied to the mechanical system of interest, magnitude and direction of the external forces are assumed to be uncertain. In this probabilistic framework, forces are described as a random field or a set of random variables. Representation of the random objects and propagation of load uncertainties through the model are efficiently done through Karhunen–Loève and polynomial chaos expansions. We take advantage of using polygonal elements, which have been shown to be effective in suppressing checkerboard patterns and reducing mesh dependency in the solution of topology optimization problems. Accuracy and applicability of the proposed methodology are demonstrated by means of several topology optimization examples. The obtained results, which are in excellent agreement with reference solutions computed via Monte Carlo method, show that load uncertainties play an important role in optimal design of structural systems, so that they must be taken into account to ensure a reliable optimization process.

In this paper, an experimental investigation, an analytical analysis and a numerical model of a typical four-point bending test on a honeycomb sandwich panel are proposed. The honeycomb core is modelled as a single solid layer of equivalent material properties. Analytical and numerical (finite element) homogenization approaches are used to compute the effective properties of the honeycomb core. A general kinematic model (unified formulation) has been adopted and used for the modelling of honeycomb sandwich panel submitted to the bending test. A comparative study of major classes of representative theories has been considered. Qualitative and quantitative assessments of displacement, stress have been presented and discussed.

Steering knuckle is the most stress sustaining and critical component of All Terrain Vehicle (ATV). The light weight and high strength components are highly necessary for race car application. Lightweight and optimized design of steering knuckle is proposed to use in a BAJA SAE INDIA off road race car. A steering knuckle is a component over which a wheel hub is mounted for supporting the steering and braking which operates under very high stress condition. 3D CAD model was created by using Cero 3.0. Static and model analysis carried out in HYPERMESH and ANSYS software to understand its behaviour under operating conditions. A CAD model of existing steering knuckle and wheel hub is applied in the race car. Finite element analysis (FEA) method was used to predict product reactions to real-world forces, vibration and other physical effects to prove whether a product worked the way it was designed to. Where as topology optimization was use to minimize the weight of component. There was 24.09 % weight reduction for hub and 16.30% for knuckle after weight optimization performed using topology optimization. It was analyses through FEA that the models of the knuckle are below the stress values and very less deflection under the applied loads.

The research-prototype is a 4 x 5 x 2m, “topologically optimized” concrete shell that was designed and
built in ten days. The prototype and this ensuing paper aim to extend the rich legacy of form-finding to
adequately represent the complexities of scale, digital design systems and delivery mechanisms of contemporary
architectural practice. They explore synergies in early design between architecture, structural engineering, and
manufacturing.

The overarching aim of this work is to make an attempt to study the effect of FDM process parameters using ABS plastics. Numerous interactive parameters are involved in Fused Deposition Modeling (FDM) process where a small change in a single parameter or a combination of parameters may produce a considerable effect in both economical and technical factors. In the present study Acronitrile Butadiene Styrene is the material considered. The major FDM parameters such as Infill Density, Layer thickness, Shell thickness, Raster width, Air gap, Speed are considered for mechanical testing and dimensional accuracy of the printed specimens. The major parameters Layer thickness, Infill density etc have shown considerable effect over model building time, material consumption and mechanical properties of the material considered for study.

A. Saad et al. (Eds.): Soft Computing in Industrial Applications, ASC 39, pp. 105–114, 2007. springerlink.com © Springer-Verlag Berlin Heidelberg 2007 ... Pattern Recognition for Industrial Security Using the ... Fuzzy Sugeno Integral and Modular Neural Networks

The paper presents an efficient 88 line MATLAB code for topology optimization. It has been developed using the 99 line code presented by Sigmund (Struct Multidisc Optim 21(2):120–127, 2001) as a starting point. The original code has been extended by a density filter, and a considerable improvement in efficiency has been achieved, mainly by preallocating arrays and vectorizing loops. A speed improvement with a factor of 100 is obtained for a benchmark example with 7,500 elements. Moreover, the length of the code has been reduced to a mere 88 lines. These improvements have been accomplished without sacrificing the readability of the code. The 88 line code can therefore be considered as a valuable successor to the 99 line code, providing a practical instrument that may help to ease the learning curve for those entering the field of topology optimization. The paper also discusses simple extensions of the basic code to include recent PDE-based and black-and-white projection filtering methods. The complete 88 line code is included as an appendix and can be downloaded from the web site www.topopt.dtu.dk.

Cette recherche, Pour une architecture de l’écume ; Force, forme et matière dans la morphogenèse de l’architecture numérique, s’interroge sur les processus de prise de forme matérielle et leurs influences dans l’émergence de l’architecture numérique. La première partie de la thèse porte d’abord un regard historique, comme théorique, sur trois différentes phases dans la relation entre forme, force et matière. Par une analyse biologique, philosophique et physique, nous expliciterons une multitude de concepts, et leurs influences sur l’architecture ; elle qui se trouvera, à regret, sans cesse en retard face à eux. Ces idées pourront sembler éloignées, au premier abord, mais elles viendront peu à peu ficeler une nouvelle approche à l’architecture, celle du système matériel. De plus, la technologie numérique sera au cœur de cette convergence, ce qui facilitera le mélange du savoir multidisciplinaire, par la création de plates-formes de communication générales.
Ensuite, la deuxième partie nous transporte vers l’architecture de l’écume. Nous débutons avec l’analyse morphogénétique de ces mousses savonneuses, ainsi que leur parallèle dans l’architecture expérimentale, des années 1950 jusqu’à aujourd’hui, pour y exposer leurs possibilités spatiales et atmosphériques. Il s’agit d’une démonstration des possibilités reliées à l’intégration des théories, mises en place dans la première partie, dans la conception d’un système matériel, inspiré des agrégations poly-sphériques et des solides cellulaires. Une méthodologie numérique exhaustive y est développée, allant de la génération algorithmique de l’écume, à sa fabrication numérique, en passant par l’optimisation topologique de sa structure matérielle.

This paper outlines the fundamentals of the methods of exergy analysis and entropy generation minimization (or thermodynamic optimization*the minimization of exergy destruction). The paper begins with a review of the concept of irreversibility, entropy generation, or exergy destruction. Examples illustrate the accounting for exergy #ows and accumulation in closed systems, open systems, heat transfer processes, and power and refrigeration plants. The proportionality between exergy destruction and entropy generation sends the designer in search of improved thermodynamic performance subject to "nite-size constraints and speci"ed environmental conditions. Examples are drawn from energy storage systems for sensible heat and latent heat, solar energy, and the generation of maximum power in a power plant model with "nite heat transfer surface inventory. It is shown that the physical structure (geometric con"guration, topology) of the system springs out of the process of global thermodynamic optimization subject to global constraints. This principle generates structure not only in engineering but also in physics and biology (constructal theory).

Single-phase multilevel converters are suitable for medium power applications as photovoltaic systems and switched reluctance machines. An overview of possible modulation methods including carrier-based pulse width modulation and space vector modulation techniques for multilevel single-phase converters is presented. A new space vector modulation for this type of converters is proposed. This space vector modulation method is very simple presenting low computational cost. Different solutions for the space vector modulation are presented achieving similar output results but imposing restrictions on the power converter topology. Optimization algorithms balancing the DC-link voltage or minimizing the commutation losses are presented. Experimental results using a 150 kVA five-level diode- clamped converter are shown to validate the proposed modulation and optimization methods.

Additive manufacturing (AM) or, more commonly, 3D printing has grown in double digits in past years. It has shown its potential example in the medical, automotive, aerospace, and spare part sectors. Personal manufacturing, complex and optimized parts, short series manufacturing and local on-demand manufacturing are some of the current benefits. The development of new materials and equipment has opened up new application possibilities, and equipment is quicker and cheaper using the new materials launched by vendors and material developers. AM has become more critical for the industry but also for academics. Since AM offers more design freedom than any other manufacturing process, it provides designers with a new challenge to design better and more efficient products.

The objective of this Special Issue was to provide a forum for researchers and practitioners to exchange their latest achievements and to identify critical issues and challenges for future investigations of the design and applications of additive manufacturing. The Special Issue consists of 5 original full-length articles on the topic

Topology optimization approach is considered among the most interesting fields of structural optimization. In this paper topology optimization for compliance minimization using method of moving
asymptotes MMA is presented. This method is considered as a general and flexible optimization method, where it can handle any kind of objective function and any number of constraints. The effect of changing
the lower and upper asymptotes on the optimization process convergence is studied for seeking the demanded convergence with more stability and minimum time as possible. Topology optimization of different models such as a cantilever beam and simply supported beam for two and three-dimensional structure is accomplished. Also, a comparison between Method of Moving Asymptotes (MMA) and different methods such as Sequential Quadratic Programming (SQP), Optimality Criteria (OC), and Hybrid Cellular Automata (HCA) is made according to the compliance value, time consumed and the resulted topological shape.

This report presents an investigation into combining Fused Deposition Modelling (FDM) with Powder Metallurgy (PM) to fabricate metal parts. Specimens were printed using a commercially available Copper-PLA composite filament, and then heat treated to remove the PLA (debinding) and chemically consolidate the copper powder (sintering). The quality of the resulting heat-treated specimens was assessed, and their tensile properties was established. Furthermore, an attempt to fabricate a Topology Optimised heatsink was made to investigate the possibility of applying the FDM-PM process for this application.
The heat-treated parts had a final sintered density 46% of solid copper. This is significantly less than the 70-95% achieved with traditional PM methods. The poor sintered density was reflected in the tensile tests, which confirmed that the sintered copper specimens were weaker than the Copper-PLA specimens. Furthermore, an attempt to fabricate the TO heatsink was unsuccessful based on the extensive damage caused to the model during heat-treatment. 
Whilst the results presented in this report do not suggest the FDM-PM process as a suitable method of fabricating metal parts, it should be noted that the furnace used for heat-treatment was an open environment one. Despite the specimens being encased in a protective refractory material, a certain amount of oxidisation of the parts was still inevitable. Whilst the extent of oxidisation was not quantitively confirmed, it is suspected that this was a large factor effecting the quality of the sintered parts. Further work is needed to assess the quality and mechanical properties of sintered parts using a controlled environment furnace, which would negate the effects of oxidisation.

The introduction of digital tools in the architectural practice has led to a strong convergence with the ield of engineering, opening a discussion focused on the technical performances of structures. his paper ofers a theoretical background to the dialogue, with the exploration of diferent aspects of the form inding process, which is express by the continuous interaction between form, force and matter. The intentions here are to describe a fraction of the ideas that led to an architecture digitally informed by the material characteristics. It all starts with a critique of the Aristotelian’s hylomorphism by the introduction of force in the relation between form and matter. hat will lead to an understanding of matter as an intensive and metastable entity. hese theories of the twentieth century now ind echoes in the most advanced digital processes, such as topological optimization of structures. These algorithmic protocols can literally integrate an associative relation between form, force and matter, within the whole design process. The generation of these intensive «material forms» are now questioning diferent notions of structure and space in contemporary architecture.

Current computational paradigms in architecture are increasingly focusing on bridging between design and fabrication in order to take advantage of novel production technologies. However, the dominant surface modelling approach of CAD packages is unable to exploit their full potential. Moreover, the conceptualization of materials in design still relies on continuous and isotropic description, hence needing translation from digital design to analog production. This paper proposes a novel design and fabrication concept combining current developments in voxel-based design with research into a novel concept of materials as " digital " entities. Relying on voxel-based approaches, a topology optimization algorithm is used to determine density distribution of material under user-defined load and support condition. To overcome scale and reversibility limitations, the resulting density field is used as driver for the aggregative growth of modular components, approximating the optimized material allocation. The sequential nature of the algorithm employed allows the integration of fabrication constraints. Finally, a method for fast evaluation and optimization of stability conditions of the resulting assembly is proposed. Such approach aims at allowing the application of voxel-based design and topology optimization processes at the architectural scale.

Structural topologies obtained by SIMP are not completely satisfactory since they exhibit areas with intermediate densities which lack physical meaning. Thus, the designer is left with the nontrivial decision of rounding and approximating the solution. This paper presents SA–SIMP, a hybrid methodology that couples simulated annealing and SIMP under a look-ahead scheme that gradually fixes or removes elements with intermediate densities (i.e., gray areas in SIMP). After designing several strategies and testing them on different structures, SA–SIMP consistently led to topologies with both lower compliances and less gray areas than those obtained by SIMP alone.

In this study, topology optimization of a jet engine bracket which was proposed from GE Aviation challenge for improving the brackets is presented using finite element analysis (FEA). The minimum mass, maximum equivalent stress and first natural frequency are selected for the objective functions to topology optimization. Then, topology optimization procedure is implemented according to the identified boundary conditions and objective functions. Finally, the manufacturing model is obtained and compared with the original model according to the maximum equivalent stress, mass reduction and first natural frequency. Also, modal analysis and static analysis results of the proposed models are presented.

Horizontal band saw machine is an important machine tool in mechanical workshop. This paper is about Weight reduction of fix jaw of rear vice. Rear vice used for clamping work piece during cutting operation. It has two jaws Fix jaw and movable jaw. Movable jaw attached to hydraulic cylinder which applies force to hold work piece between these two jaw. Reduce weight of components help to minimize load on environmental resources .This efforts for reduction of weight by using topology optimization. fix jaws has been modeled using solid works First conducted analysis on existing jaws with calculating the forces acting on jaws in order to find out Max. Displacement and stress induced. These analyses were carried using Altair Hyperworks and solver used is optistuct. Again conducted topology optimization with applying manufacturing constrain like minimum member size and single type draw direction. Again prepare cad model based on topology result and carried analysis on optimized model. from the analyzed results, Displacement and stress are lower than existing model. From result it was found that current design is safe also save material and cost of component, Finally we reduced total weight by 12 % of current fix jaw model. Topology optimization analysis is carried out in Hyperworks which yielded in weight optimized.

This paper presents a novelapproach for constrained B-Spline curve approximation based on the Force Density Method (FDM). This approach aims to define a flexible technique tool for curve fitting, which allows approximating a set of points taking into account shape constraints that may be related to the production process, to the material or to other technological requirements. After a brief introduction on the property of the FDM and the definition of the network usedfor the formulation of the fitting problem, the paper explains in detail the mathematical approach, the methods and the techniques adopted for the definition of the proposed constrained B-Splinecurve approximation. The results suggest that the adoption of a mechanical model of bar networks allows developing a more flexible tool than the traditional least squared methods (LSM) usually adopted for fitting problems. Numerical examples show that the new approach is effective in fitting problems when the satisfaction of shape constraints, such as those related to production orto technological processes, are required.

Unlike the traditional topology optimization approach that uses the same discretization for finite element analysis and design optimization, this paper proposes a framework for improving multiresolution topology optimization (iMTOP) via multiple distinct discretizations for: (1) finite elements; (2) design variables; and (3) density. This approach leads to high fidelity resolution with a relatively low computational cost. In addition, an adaptive multiresolution topology optimization (AMTOP) procedure is introduced, which consists of selective adjustment and refinement of design variable and density fields. Various two-dimensional and three-dimensional numerical examples demonstrate that the proposed schemes can significantly reduce computational cost in comparison to the existing element-based approach. Copyright © 2012 John Wiley & Sons, Ltd.

In this paper, a displacement-constrained volume-minimizing topology optimization model is present for two-dimensional continuum problems. The new model is a generalization of the displacement-constrained volume-minimizing model developed by Yi and Sui [1] in which the displacement is constrained in the loading point. In the original model the displacement constraint was formulated as an equality relation, which practically means that the number of " interesting points " may be exactly one. The recent model resolves this weakness replacing the equality constraint with an inequality constraint. From engineering point of view it is a very important result because we can replace the inequality constraint with a set of inequality constraints without any difficulty. The other very important fact, that the modified displacement-oriented model can be extended very easily to handle stress-oriented relations, which will be demonstrated in the forthcoming paper. Naturally, the more general theoretical model needs more sophisticated numerical problem handling method. Therefore, we replaced the original " optimality-criteria-like " solution searching process with a standard nonlinear programming approach which is able to handle linear (nonlinear) objectives with linear (nonlinear) equality (inequality) constrains. The efficiency of the new approach is demonstrated by an example investigated by several authors. The presented example with reproducible numerical results as a benchmark problem may be used for testing the quality of exact and heuristic solution procedures to be developed in the future for displacement-constrained volume-minimization problems.

The ant colony optimization (ACO) algorithm, a relatively recent bio-inspired approach to solve combinatorial optimization problems mimicking the behavior of real ant colonies, is applied to problems of continuum structural topology design. An overview of the ACO ...

Using continuous variables in truss structural optimization results in solutions which have a large number of different cross section sizes whose specific dimensions would in practice be difficult or expensive to create. This approach also creates optimal models which if varied, even slightly, result in structures which do not meet constraint criteria. This research proposes the discretization of cross section sizes to standard sizes of stock produced for the particular cross section and material, and a 1mm precision for node location when using shape optimization. Additionally, Euler buckling constraints are added to all models in order to achieve optimal solutions which can find use in practical application. Several standard test models of trusses from literature, which use continuous variables, are compared to the discrete variable models under the same conditions. Models are optimized for minimal weight using sizing, shape, topology, and combinations of these approaches.

Crashworthiness design is an evolving discipline that combines vehicle crash simulation and design synthesis. The goal is to increase passenger safety subject to manufacturing cost constraints. The crashworthiness design process requires modeling of the complex interactions involved in a crash event. Current approaches utilize a parametrized optimization approach that requires response surface approximations of the design space. This is due to the expensive nature of numerical crash simulations and the high nonlinearity and noisiness in the design space. These methodologies usually require a significant effort to determine an initial design concept. In this paper, a heuristic approach to continuum-based topology optimization is developed for crashworthiness design. The methodology utilizes the cellular automata paradigm to generate three-dimensional design concepts. Furthermore, a constraint on maximum displacement is implemented to maintain a desired performance of the structures synthesized. Example design problems are used to demonstrate that the proposed methodology converges to a final topology in an efficient manner. Downloaded From: http://mechanicaldesign.asmedigitalcollection.asme.org/ on 03/28/2013 Terms of Use: http://asme.org/terms 061013-2 / Vol. 131, JUNE 2009 Transactions of the ASME Downloaded From: http://mechanicaldesign.asmedigitalcollection.asme.org/ on 03/28/2013 Terms of Use: http://asme.org/terms

The objective of this work is to perform optimum design of 3D steel structures having perforated I-section beams. The optimization problem is formulated as a combined sizing, shape and topology optimization problem. The cross-sectional dimensions of the columns and beams constitute the sizing design variables, while the number and size of the web openings of the beams constitute the topology and shape design variables, respectively. Two distinctive formulations of the optimization problem are considered depending on the finite element discretization implemented for simulating the structural elements. The two formulations, corresponding to beam and shell discretization, are compared in terms of the optimum designs achieved. A characteristic test example considered, showed that a quantifiable reduction in the weight of the structure is accomplished by allowing web openings in the beams of the structure without reducing structural strength or serviceability requirements.

Single-Phase multilevel converters are suitable for medium power applications as photovoltaic systems and switched reluctance machines. An overview of possible modulation methods including carrier-based Pulse Width Modulation and Space Vector Modulation techniques for multilevel single-phase converters is presented. A new space vector modulation for this type of converters is proposed. This space vector modulation method is very simple presenting low computational cost. Different solutions for the space vector modulation are presented achieving similar output results but imposing restrictions on the power converter topology. Optimization algorithms balancing the DC-Link voltage or minimizing the commutation losses are presented. Experimental results using a 150 kVA five-level diodeclamped converter are shown to validate the proposed modulation and optimization methods.

Additive manufacturing or, more commonly, 3D printing is one of the fundamental elements of Industry 4.0. and the fourth industrial revolution. It has shown its potential example in medical and dentistry, automotive, aerospace, and spare parts [1,2,3,4,5]. Personal manufacturing, complex and optimized parts, short series manufacturing and local on-demand manufacturing are some of the current benefits. Development of process and materials in terms of speed, costs and availability open new business cases all the time. Most of the research has focused on material and AM process development or effort to utilize existing materials and processes for industrial applications. However, improving the understanding and simulation of materials and AM process and understanding the effect of different steps in the AM workflow can increase the performance even more. The best way of benefit of AM is to understand all the steps related to that—from the design and simulation to additive manufacturing and post-processing ending the actual application.

The purpose of prototyping is to validate the material and geometrical shape of the design created for a product. The properties and quality of the prototype created plays a vital role in validating the design. The selection of an appropriate process parameters for making the prototype has more influence over the mechanical properties and quality characteristics of the finished prototype. In other words, the success and market life of a product entirely relies upon the prototyping results. Rapid prototyping techniques generally involve numerous process parameters which need to be optimized to build a prototype with superior performance. Fused deposition modeling is one of the familiar and fascinating RP technique which has gained interest in the field of prototyping products of Engineering, Architecture, Medical, Automotive and Aerospace due to its simplicity and flexibility in creating conceptual models and functional parts with desired quality. In the present work Impact Hammer testing of FDM processed PolyEthylene Terephthalate Glycol-modified(PET-G) and Acronitrile Butadiene Styrene (ABS) plastics is conducted to observe the influence of FDM process parameters. The major FDM parameters such as Infill Density (ID), Layer Thickness (LT) and Printing Speed (S) are considered to obtain Frequency Response Function (FRF) for PET-G and ABS plastics. The test results have shown considerable changes in vibration properties (Frequency and amplitude) in both the materials. A 23 (2 Levels, 3 Factors) design L4 Orthogonal Array is created using Minitab 17.0 is used for conducting the experiments.

Cellular Automata (CA) models have been used to simulate complex biological and physical phenomena. In previous research, CA principles were applied to solve topology optimization problems using the Hybrid Cellular Automata (HCA) method. This method combines local evolutionary design rules with finite element analysis. Different control strategies, incorporated into the design rules, seek to minimize the error between a local mechanical signal and its optimum value. The HCA algorithm has demonstrated to be an efficient computational technique since optimal (black and white) topologies are obtained after a few iterations without checker-board patterns. With a change in the objective function, the HCA algorithm was extended for topology synthesis of compliant mechanisms with trajectory constraints. Recently a methodology based completely on cellular automaton models was developed for structural analysis and design, where the evolutionary analysis rules are derived from the plain stress state equations and the design rules from the Karush-Kuhn-Tucker (KKT) conditions for structural topology optimization. The methodology has demonstrated that there is no need to use finite element analysis for solving topology optimization problems. This investigation concerns the extension this methodology to the synthesis of compliant mechanisms. The algorithm is applied to two dimensional models. The results are compared with the ones obtained using other approaches. 2.

Functionally graded materials (FGMs) are a new class of bio-inspired composite materials made from different material phases, in which their volume fraction changes gradually towards a particular direction. Accordingly, continuous changes in the composition, microstructure and porosity of the graded materials results in material properties gradients; for this reason, the material properties move smoothly and continuously from one surface to another, eliminating the interface problem. Hence, with appropriate design, FGMs can develop better properties than their homogeneous counterpart due to their better designability. One potential employment of FGMs is as damper or energy absorber in dynamic applications, in which optimization techniques such as the topology optimization method (TOM) can contribute to a better performance in relation to a non-optimized design. In this chapter, functionally graded structures are designed with and without the TOM in order to explore the advantages of the FGM concept in low-velocity impact condition, which is a special case in the world of dynamic analysis, and has interest for designing machinery parts and components.

In this paper, a parameterization level set method is presented to simultaneously perform shape and topology optimization of compliant mechanisms. The structural shape boundary is implicitly embedded into a higher-dimensional scalar function as its zero level set, resultantly, establishing the level set model. By applying the compactly supported radial basis function with favorable smoothness and accuracy to interpolate the level set function, the temporal and spatial Hamilton–Jacobi equation from the conventional level set method is then discretized into a series of algebraic equations. Accordingly, the original shape and topology optimization is now fully transformed into a parameterization problem, namely, size optimization with the expansion coefficients of interpolants as a limited number of design variables.Design of compliant mechanisms is mathematically formulated as a general optimization problem with a nonconvex objective function and two additionally specified constraints. The structural shape boundary is then advanced as a process of renewing the level set function by iteratively finding the expansion coefficients of the size optimization with a sequential convex programming method. It is highlighted that the present method can not only inherit the merits of the implicit boundary representation, but also avoid some unfavorable features of the conventional discrete level set method, such as the CFL condition restriction, the re-initialization procedure and the velocity extension algorithm. Finally, an extensively investigated example is presented to demonstrate the benefits and advantages of the present method, especially, its capability of creating new holes inside the design domain.

The timber frame represents a central structural system in historical Chinese buildings [1]. The Dougong (bucket arch joint) is an independent class of joints widely applied in traditional Chinese timber frame construction systems [2]. It is also a primary structural component for transferring the loads from the roof to the pillar [3]. However, the application of the Dougong in contemporary architecture is limited due to the complexity of its production procedure [4]. The scope of this research is to re-elaborate the Dougong joint and its related components, introducing parametric design and robotic fabrication in order to produce and assemble the new joint in contemporary timber architecture.  The paper finds its roots in our previous research which explored the application of robotic technologies for the fabrication of traditional Chinese timber joints [5] and the reinterpretation of the Dougong joint using parametric tools and robotic fabrication techniques [6]. It investigates which existing robotic technologies are appropriate for the automation assembly and production of the Dougong joint through reviewing relevant researches conducted in the field of parametric design and digital fabrication about the Dougong and its related timber components. Consequently, it addresses the following research questions:
• Which existing robotic technology would be more suitable for applying the Dougong joint in modern architecture?
• What are the advantages/disadvantages of utilising robotic technologies in constructing and assembling timber components related to the Dougong joint?
To answer the questions, we review systematically and analyse comparatively ten articles filtered through 1509 publications searched by using the keywords timber, digital fabrication, and robotics, from five databases: Elsevier's abstract and citation database (Scopus), the Institute of Electrical and Electronics Engineers (IEEE), Engineer village, Cumulative Index about publications in Computer Aided Architectural Design (CumlnCAD) and ScienceDirect. The articles are analysed by focusing on four different aspects such as robot types, robotic end-effectors, robotic firmware, and complementary robotic tools. Our findings include the benefits and challenges of existing robotic technologies in relation to the parametric fabrication of the Dougong joint. Furthermore, they highlight the advantages and disadvantages of the ten research projects and evaluate their suitability for reinventing the Dougong joint into a system suitable for contemporary architecture